This invention relates to adhesive compositions and their cured products, especially to adhesive silicone compositions of the self adhesive type and their cured products.
Currently, various types of adhesives such as polyurethane resins, acrylic resins, epoxy resins, and silicones are employed for the bonding of electric and electronic parts and for use as construction sealing agents. Among these, silicone type adhesives are most popularly utilized due to their superiority in heat resistance, weather resistance, electrical characteristics, and in the relaxation of stresses caused by heating and cooling.
Many proposals are still reported for these silicone type adhesives in order to further improve their adhesiveness. For example, compounds listed below have been proposed to be added as adhesion promoters: an organopolysiloxane with trialkoxy silyl groups and hydrogen atoms bonded to silicon atoms (reference: U.S. Pat. No. 3,699,072), an organopolysiloxane with hydrogen atoms bonded to silicon atoms and ester groups and/or glycidyl groups (reference: Japanese Patent application KOKAI (Laid Open) 50-39345), and reaction products between aminoalkyl alkoxysilane and glycidyloxy alkyl alkoxysilane (references: U.S. Pat. No. 3,837,876 and Japanese Patent Application KOKOKU (Examined) 55-41702).
However, none of the proposals based on the previous technologies as described above have improved adhesiveness to a satisfactory level. A severe deterioration in adhesiveness is especially observed when adhesives are stored at room temperature, or at higher temperatures, prior to usage. Further, the recent trends in energy conservation, and the utilization of materials which are difficult to adhere, demand silicone type adhesives which are particularly good with respect to their adhesiveness when cured at low temperature. However, such adhesives fulfilling the above demands have not been identified.